CVE-2026-90979 Apache Karaf: LDAP filter injection in JAAS LDAP login modules

High 7.3 Published 28 Sep 2026 Updated 30 Sep 2026

Attackers can inject LDAP filters via crafted usernames in specific login modules to bypass authentication or escalate privileges.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-90979?

CVE-2026-90979 is a high-severity vulnerability in Apache Karaf, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

LDAPCache and LDAPBackingEngine build LDAP search filters for user lookup and role lookup by textually substituting the placeholders %u, %dn, and %fqdn (drawn from the login name, the resolved user DN, and its fully qualified namespace form) into administrator-configured filter templates (userFilter, roleFilter). Before the fix, the only sanitization applied to the substituted value was double backslashed:

filter = filter.replaceAll(Pattern.quote("%u"), Matcher.quoteReplacement(user));

filter = filter.replace("\\", "\\\\");

This does not escape the other characters RFC 4515 requires escaping in an LDAP search filter: *, (, ), and NUL. A login name containing any of these can change the structure of the resulting filter rather than being matched as a literal value (e.g. a crafted username can turn an equality match into a wildcard match, or close/reopen filter clauses), widening what the search returns and potentially causing a login or role lookup to match an LDAP entry other than the intended one, over-granting roles, and depending on deployment-specific filter templates, potentially affecting which account a login resolved to.

It's not exploitable through every entry points: LDAPLoginModule and LDAPPubkeyLoginModule both called Util.doRFC2254Encoding() (correct RFC 4515 escaping) on the login name before handing it to LDAPCache, which masked the missing escaping in LDAPCache for those two call paths. Using LDAPCache directly (bypassing the login modules) does not reproduce through the normal LDAPLoginModule/LDAPPubkeyLoginModule authentication flow for this reason. It does reproduce through two other call paths that reach LDAPCache/LDAPBackingEngine without any prior escaping:

* GSSAPILdapLoginModule passes the NameCallback name straight through, unescaped. * LDAPBackingEngine (listRoles) passes principal.getName() straight through, unescaped.

Weakness: CWE-90

Which versions are affected by CVE-2026-90979?

It affects 1 product.

Products include Apache Karaf.

How do I fix CVE-2026-90979?

No fix has been published for CVE-2026-90979 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-90979 being exploited?

There is no known exploitation of CVE-2026-90979 in the wild and no public exploit code.

Sources

Also known as GHSA-932c-qw9f-cpcq.